Model reduction of a flexible multibody system with clearance

• Component mode synthesis is used to reduce the degrees of freedom of flexible multibody systems with clearance.
• Reducing system equation of motion of a flexible multibody system with clearance is established.
• Important issues as the proper selection of the component modes and the convergence properties of the model reduction technique are studied.

A system reduction scheme related to a flexible multibody system with clearance is devised. In this work, the absolute nodal coordinate formulation is used to model the flexible multibody system, while imperfect joint is modeled as dry clearance joint or lubricated revolute joint. Meanwhile, the component mode synthesis is applied to reduce the size of the matrices. Finally, numerical examples are posted to analyze the proper selection of component modes and the convergence properties of the model reduction technique. It is obvious that the results of the reduced model are close to the results of the original model when the error of the maximum deformation energy between the reduced model and the original model is very small. The results of the reduced model with lubricated revolute joint can achieve high calculation accuracy with fewer modes than those with dry clearance joint.